Patients all over the world are denied the minor comfort of diagnoses for their illnesses—doctors are baffled by new diseases, and they have no name to give them or treatments to recommend.

The sources of many such illnesses also have not been identified. Some new illnesses may, however, be caused by the human body’s incompatibility with modern chemicals and other conditions it has not had to cope with in history. Daniel Lieberman, a biology professor at Harvard University has written about common diseases such as asthma, diabetes, and irritable bowel syndrome, that may be caused by the modern lifestyle.

National Institutes of Health (NIH) has an Undiagnosed Diseases Program dedicated to unraveling the mysteries of new diseases. Syndrome Without a Name (SWAN) groups have popped up around the world to support people living in uncertainty with undiagnosed diseases.

Here’s a look at seven rare diseases that have been identified in recent years, though much remains to be learned about them and the causes of some are a complete mystery.

“Chemtrails believers claim governments around the world are in cahoots with secret organizations to seed the atmosphere with chemicals and materials—aluminum salts, barium crystals, biological agents, polymer fibres, etc.—for a range of nefarious purposes. These include controlling weather for military purposes, poisoning people for population or mind control, and supporting secret weapons programs.”

The Mayo Clinic describes the disease as “an unexplained skin disorder characterized by disfiguring sores and crawling sensations on and under the skin. Morgellons disease also features fibers or solid materials emerging from these sores.”

4. Mysterious Calcium Build-Up in the Arteries and Joints

NIH’s Undiagnosed Diseases Program announced it’s first major success in 2011 when it diagnosed and learned more about a rare condition caused by a buildup of calcium in the arteries and in the joints. Before 2011, when NIH encountered the disease in nine individuals from three families, it was only recorded in seven patients over the course of a century.

NIH named it “arterial calcification due to CD73 deficiency” (ACDC). It initially baffled doctors, because the calcium was found to build up in a way doctors did not previously know was possible in the body.

5. One Woman’s Story of Unexplained Blindness

DeGalynn Wade, an attorney in Minneapolis, went blind and doctors could not figure out why. The symptoms that accompany other illnesses that cause blindness could not be found in her body. She turned to NIH’s program for help, reported The Guardian, though the cause of her blindness remains a mystery.

6. Idiopathic Environmental Intolerance (IEI)

The World Health Organization (WHO) has labeled as “Idiopathic Environmental Intolerance” illnesses that may be caused by exposure to multiple chemical substances and to electromagnetic fields common in modern society.

The “idiopathic” part means the exact cause is unknown.

WHO reported last year that “research has not been able to provide support for a causal relationship between exposure to electromagnetic fields and self-reported symptoms, or ‘electromagnetic hypersensitivity.’”

People who may be sensitive to electromagnetic fields report symptoms such as headaches, difficulty concentrating, joint and muscle pain, dizziness, and nausea.

CDC explains on its website: “[S. aureus] is the primary cause of lower respiratory tract infections and surgical site infections and the second leading cause of nosocomial bacteremia, pneumonia, and cardiovascular infections.”